1. Field of the Invention
The present invention relates to a calibration method using a sensor, and more particularly, to a calibration method for compensating an offset occurring when a driving element such as a motor and a belt in a transmission part attached to a body of the robot or a sensor for sensing the movement of a shaft of an arm in the robot is exchanged with a new one.
2. Prior Art
When a mechanical appliance requiring a precise position control such as an industrial robot undergoes a troubleshooting on a part or entire parts thereof, or it is disassembled and assembled in order to exchange parts therein with new ones, an offset may occur which is a variation of the initial position of a moving part such as an arm in the robot from a preset position thereof. Such an offset results in the reduced accuracy of the position control on the basis of the preset calibration data. Therefore, a new calibration should be necessarily performed so that the preset calibration data are amended, in order to compensating the offset after the parts are exchanged with new ones.
In conventional art, if the offset has to be compensated after the parts in a robot body such as a motor are exchanged, the calibration has been performed by utilizing a jig for exclusive use in calibration, or on the basis of marks signed on the robot body.
The calibration using the calibration jig is performed according to the following steps.
(1) detaching a working tool attached to the robot body. PA0 (2) attaching a calibration tool. PA0 (3) performing calibration using the calibration tool. PA0 (4) amending calibration data or compensating an offset with the performed calibration results. PA0 (5) detaching the calibration tool. PA0 (6) attaching the working tool again. PA0 (1) moving every part of the body to the marked positions. PA0 (2) amending the calibration data or compensating the offset using the present position of the robot.
Such a calibration method using the calibration jig requires a high preciseness of the calibration jig. Further, the working tool and the calibration tool must be exchanged with each other two times, so the calibration process is very troublesome and much time is consumed, which may cause a lowering of productivity.
Meanwhile, the calibration using the marks inscribed on the robot body is performed according to the following steps.
Such a method does not bring about the troublesome job of exchanging the tools as the case of utilizing the calibration jig, however, that method is not preferable since the preciseness of the calibration is low.